![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512629_8.jpg)
Will need
- 3.7V lithium battery (fully charged 4.2V).
- Light-emitting diode any color.
- Two resistors of 1 kOhm and 5.6 kOhm.
- Transistor optocoupler PC817.
- Capacitor 220 uF 10 V.
Making a flasher using an optocoupler
First, let's take a look at the optocoupler itself. It consists of two elements united by optical communication. That is, if you apply voltage to Light-emitting diode, the transistor inside will open.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512617_1.jpg)
Note that the dot represents the first contact for reference. The element itself has 4 contacts. 1, 2 - this is the input for connecting internal LED. 3, 4 - output from the transistor.
Simple flasher circuit
On the basis of this simple radio element, a simple multivibrator is built - a generator of repeating pulses.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512589_6.jpg)
The circuit does not require adjustment and, with fully functional elements, starts working immediately.
Assembly is carried out by hanging installation without a board.We clamp the optocoupler in the clamp and solder two resistors according to the diagram.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512666_2.jpg)
Next we solder Light-emitting diode. Pay attention to the polarity of its inclusion.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512592_3.jpg)
Next we solder the capacitor.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512666_4.jpg)
The connecting tracks are made from tinned wire.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512619_5.jpg)
We bring the scheme to the end.
Examination
Solder the battery contacts.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512622_7.jpg)
The flasher starts flashing. It's simple.
![LED flasher on optocoupler](https://i.washerhouse.com/uploads/posts/2019-09/1567512629_8.jpg)
The blinking frequency can be adjusted by the capacitor capacitance.
If suddenly something does not start, check the polarity of all elements except resistors.
I think you can easily find a use for this simple scheme.
Watch the video
You can evaluate the operation of the flasher in the video.